Improvement in smelting iron ores



UNITED STATES PATENT GEEIGE.

IMPROVEMENT lN SMELTING IRON ORES.

Specification forming part of Letters Patent No. 116,558, dated July 4,1871.

To all whom 'it may concern:

Be it known that I, CHARLES GocERANE, of The Ellowes,7 Upper Gornal, inthe county of Stafford, England, have invented an Improved Mode of, andApparatus, Kiln, or Furnace for, Preparing Iron Ores for Smelting; anddo hereby declare that the following description, taken in connectionwith the accompanying drawing,

hereinafter referred to, forms a full and eXact specification of thesame, wherein I have set forth the nature and principles of my saidimprovement, by which my invention may be distin guished from others ofa similar class, together with such parts as I claim and desire tosecure by Letters Patent-that is to say:

My invention has reference to the process of deoxidizing iron ores,before introduction into the blast-furnace, by subjecting the same tothe action of carbonic-oxide gas; and consists of an improved method,whereby, instead of acting upon cold-iron ore with highly-heatedcarbonicoXide or blast-furnace gas, as described in the specification toanother patent for which I am applying, or instead of simultaneouslyheating the ore and the carbonic-oxide gas, as is effected to a certainextent in the iblast-furnace, and as has also otherwise been proposed,the iron ore is first heated to the requisite degree in one part of aspecial furnace or kiln, and then in another part of such kiln issubjected to the action of carbonio-oxide or blast-furnace gas, whichhas not been specially heated for this purpose.

Various arrangements may be employed for carrying this invention intopractice. Thus in one arrangement I introduce the ore into a chamber orkiln, at or near the lower end of which cool carbonio-oxide orblast-furnace gas is made to enter, which gas, after ascending throughthe lower stratums of the ore, is, in the upper part of the kiln,(constituting a combustion-chamber which may or may not be separatedfrom the lower part or reducing-chamber of the kiln,) brought intocontact with jets of atmospheric air, and, in entering into combustiontherewith, is caused to heat the ore contained in suchcombustion-chamber to the requisite degree before it descends into thereducing-chamber of the kiln, where it is acted upon by thecarbonio-oxide gas, and

whence it afterwards issues through chutes at the bottom. By thisarrangement the heat contained in the ore is utilized by being taken upby the gas on its way to the combustion-chamber, the ore passing awayfrom the kiln in a comparatively cool state, and thus the loss of heatarising in the before-mentioned processes through the passing away ofthe ore in a highly-heated condition is prevented. In this arrangement asucient quantity of carbonio-oxide or blast-furnace gas must beintroduced into the reducingchamber to afford the requisite surplus ofunconverted gas after passing through the ore for producing thenecessary heat by combustion with the air in the combustion-chamber. Inanother arrangement the necessary quantity of combustible gas isintroduced directly and separately into the combustion-chamber, and onlysuch a quantity of carbonio-oxide or blast-furnace gas is passed intothe reducing-chamber as is requisite for deoxidiziug the ore. The heatof such gas, if any is left after passing from the reducingchamber, may,if desired, be utilized by causing the gas to pass in contact with thepipes or iiues conducting the air or combustible gas, or both, into thecombustion-chamber, or the hot gas may be allowed to rise up among theore in the combustion-chamber.

Having thus set forth the nature of my invention, I will now proceedmore particularly to describe the manner in which it is to be performed,for which purpose I shall refer to the accompanying drawing, showing oneof the various arrangements of kilns or furnaces by which my inventionmay be carried into effect.

Figure l on Sheet I shows a vertical section of the kiln. Fig. 2, SheetI, shows a sectional plan of the same on line X X, Fig. l. Figs. 3 andAL, on SheetII, show, respectively, an enlarged section on line Y Y Fig.4, and a section on line Z Z, Fig. 3, of one ofthe discharging-boxes.

Similar letters of reference indicate similar parts in each of thefigures.

The furnace or kiln consists of a chamber, A,"

of fire-brick, inclosed in an iron casing, which chamber is closed atits upper end by a bell- Valve, B, above which is a closedfeeding-hopper, C, for the introduction of the ore, for the constructionof which Letters Patent for Great Britain and Ireland have been grantedto me, bearing date 21st February, 1868, No. 579. The lower end of the`chamber A is supported by columns I I, and is contracted to afunnel-shape at A', into the center of which rises the passage forcarbonio-oxide or blast-furnace gas D, terminating in a conical orifice,D, covered by a conical hood, E, so that the gases passing from thepassage D issue into the kiln from under the edge of the hood E. Theannular` space formed between the sloping sides A of the chamber A andthe surface of the conical orifice D has a number of outlet-apertures,F, connnunicating with the iron discharge-boxes G, fixed by their upperends in an air-tight manner to and suspended from the ironcasing of thekiln. Between the outlet-apertures F are formed ridges F to prevent thelodging of ore in the spaces between the apertures. The construction andmode of operating the discharge-boxes G will be more readily understoodon reference to the enlarged views thereof shown on Sheet II. In orderto discharge the reduced ore from the kiln without at the same timeallowing atmospheric air to enter the kiln through the dischargeboxes,each box is provided with three sets of slides, Hl H2 H3, of which thoseH1 serve to cut off the communication between the kiln and the box,while those H2 cut of the communication between the upper part and thelower part of the box, and those H3 close the lower end of the box. Bythis arrangement, if the slides H1 are opened, (H2 being closed,) aquantity of reduced ore will fall from the kiln into the upper part ofbox. If, now, the slides Hl are closed an'd those H2 are opened, (H3being closed,) the ore contained in the upper part of the box will fallinto the lower part, and after the slides H2 have been closed, and thoseH3 are open, the ore is discharged into the trucks or onto the ground.The slides H1 Hl are opened and closed in opposite directions, re-

spectively, by means Vof the lever K, having itsY fulcrum at K, and bymeans of a pinion, L, in gear with the rack L on the slide, the spindleofthe pinion being rotated by a grooved pulley, M, fixed on the same,worked by an endless chain, N. The slides H2 are actuated in a directionat right angles to H1 by means of the levers O O working on fulcrums O Ofixed to the columns I. The slides H3 are worked by pinions P in gearwith racks on the slides, and rotated by means of crank-handles In orderto prevent any escape of carbonio-oxide gas at the slides Hl H2 theseare made to work backward and forward inside closed casings G1 G2projecting from the discharge-box G, also, in order to prevent as muchas possible the entrance of air into the lower 'part of thedischarge-box, when the slides H3 are opened for discharging the reducedore, carbonicoxide gas may be introduced into such lower space throughthe aperture G2. Should it be found at any time that the ore does notdescend readily into the discharge-boxes from the kihi, stopperedapertures It It are provided, through which prizing-bars may beintroduced, and to which access is gained from the gallery S. At someheight above the inlet D', for the carbonicoxide gas, side apertures T Tare formed round the kiln for the inlet of atmospheric air, or in orderto effect the combustion of the unconverted portion of thecarbonio-oxide gasrising up from below. The air-holes are capable ofbeing closed by stoppers T', so as to regulate the inlet of air to theexact extent required. Access is gained to the air-holes from thegallery U.

The action of the kiln takes place as follows: The kiln being chargedwith ore, the lower portion of which may be introdued either in a heatedor cool state, and the valveB and hopper() closed, carbonica-oxide gasor blast-furnace gas, or other suitable reducing-gas, is introducedthrough the passage D into the bottom of the kiln, and in rising upthrough the heated lower portion of the ore it acts upon and deoxidizesthe same more or less completely, at the same time taking up the heattherefrom and becoming itself converted into carbonio-acid gas. Thereducing-gas is, however, introduced in such quantity as to be in excessof the amount required for reducing the ore, so that the unconvertedportion thereof, in rising up in a heated state to the level of theair-holes T, enters into combustion with the air passing in, and therebyheats the ore in the upper part ofthe kiln to the requisite degreebefore it is made to descend into the lower part, in order in its turnto be reduced by the incoming carbonic-oxide gas. The deoxidation of thelower portion of the ore having thus been effected it is discharged in acomparatively cool state into the discharging-boxes G, as beforedescribed, and fresh ore is introduced into the kiln through the valve Bat top. The carbonio-acid and other gases, in rising up through the massof ore above the air-holes T, impart their heat to the same, and finallyescape through the side aperture V into a iiue, in which a draught isproduced, either by a chimney or by an exhaust-fan, or by both. Shouldit be found that the air entering through the apertures T doesY notpenetrate sufficientlyY Y through the mass of ore to effect the equableheating of all parts of the same, this may be facilitated by causing itto pass in through perforated radial pipes W, shown in dotted lines inFig. l, leading from the apertures T to a central annular pipe, W1,connecting all the radial pipes, and supported by means of stays W2.

As before stated, the arrangement of the furnace or kiln may bevariously modified for carrying my invention into practice. Thus theupper part or combustion-chamber of the kiln may be separated from thelower part or reducing-chamber, and be furnished with a separate supplyof combustible gas for raisingthe ore to the requisite temperature; orone or more heating-chamber or chambers or retorts may be arranged atthe top of the kiln and the heated ore be discharged thence into thekiln. Also, the reducing-gas may be made to enter the kiln throughseveral side apertures instead of through one single central passage,and the discharge of the reduced ore may be effected in any otherconvenient manner, whereby the inlet of the atmospheric air into thelower part ofthe kiln is practically prevented.

Having thus set forth the nature of my invention, and in what manner thesame is to be performed, I wish it to be understood that I do not limitmyself to the precise means or apparatus for carrying the same intoeffect, as hereinbefore described, with reference to the accompanyingdrawing, as these maybevariously modified, as already stated, withoutdeparting from the nature of my invention; neither do I claim as part ofmy invention the various details of construction of apparatushereinbefore described7 except when used in combination for the purposesof my invention. Also, I am aware that kilns have before beenconstructed with a central inlet for combustible gases, covered by aconical hood, but for totally diierent purposes, namely, for calciningminerals and other substances-that is to say, for subjecting the sanieto an oxidizing flame; whereas, by my invention, the ore is subjected tothe ac tion of reducing-gases, and the introduction of oxidizinggases,as in caleining operations, is carefully avoided; but

Deoxidizing or reducing iron ores .before their introduction into theblast-furnace by first raising the ores to the requisite degree of heat,and

then subjecting the saine to the action ofcar- Witnesses Guns. D. ABEL,J No. BN. MILLARD.

